(Washington Post) – The burning sensation in the southwestern United States was diagnosed by climate scientists more than a year ago.

As California broiled in high temperatures and drought last year, academic institutions across the country released study after study that suggested rising temperatures and less moisture were part of a new normal for the state. One study by NASA predicted in February that the Southwest can expect to endure a 30-year megadrought starting as early as 2050. In early March, a study from Stanford University said California could face a drought every other year based on a 30-year trend of higher-than-normal temperatures and dwindling rainfall.

In August, Columbia University’s Earth Institute found evidence that global warming has contributed to California’s drought. And in September, NASA and Columbia teamed up to produce a study showing that five centuries have passed since the Golden State has been as dry as it currently is. Each of the studies drew on research that goes back decades.

None of the studies could explain exactly why the West is baking today. Temperatures reached 120 degrees Fahrenheit in parts of California this week. Since October, 26 million trees have died in six counties across 760,000 acres in the Sierra Nevada mountains that run along California’s spine.

That brings the number of dead trees to 66 million over four years of drought, the service said. A combination of heat, dryness and a greedy little beetle, according to the latest estimate by the U.S. Forest Service.

In Arizona, where temperatures reached 118 degrees in Yuma on Tuesday, a pair of tourists who went for a hike died on the trail under the scorching heat. A third member of their party informed authorities because he was the only one strong enough to straggle back for help.

California, Nevada, New Mexico and Arizona are experiencing large wildfires fairly early in the season. Two large fires burning near Santa Barbara are threatening to combine, and another is burning north of San Francisco, stretching thin the personnel and material needed to fight them.

When a monster wildfire struck Colorado in 2012, Sherman Harris, then-undersecretary at the Agriculture Department, which oversees the Forest Service, acknowledged that big fires driven by climate were here to stay. The wildfire season that ran from June to September expanded to include May and October.

Since then, it has gotten even worse. The season starts in March and ends in December. Once, it was rare to see 5 million cumulative acres burn in a year; recent seasons have recorded twice that. Last year’s wildfire season set a record with more than 10 million acres burned — more land than Maryland, the District and Delaware combined, the Forest Service said.

More than half the fires were in Alaska, where dryness due to historically low mountain snowpack and a freak lightning storm created perfect conditions for a huge blaze. But there were also mammoth fires in Washington and Oregon, where drought had left forests dry and ready to burn.

“The climate is changing, and these fires are a very strong indicator of that,” Sherman said in 2012, predicting what was to come. [more]